PDF10: Providing labels for interactive form controls in PDF documents

Important Information about Techniques

See Understanding Techniques for WCAG Success Criteria for important information about the usage of these informative techniques and how they relate to the normative WCAG 2.0 success criteria. The Applicability section explains the scope of the technique, and the presence of techniques for a specific technology does not imply that the technology can be used in all situations to create content that meets WCAG 2.0.

User Agent and Assistive Technology Support Notes

Description

The objective of this technique is to ensure that users of assistive
technology are able to perceive form control labels and understand
how form controls are used.

Form controls allow users to interact with a PDF document by filling
in information or indicating choices which can then be submitted for
processing. Assistive technology users must be able to recognize and
understand the form fields, make selections, and provide input to complete
the forms, and submit the form, just as sighted users can. Understandable
labels that convey the purpose of each form control are essential to
form accessibility.

Form inputs generally have labels and instructions to help users understand
what information is required and how to fill in the form. Unless these
labels are programmatically associated with the relevant fields, assistive
technology might not be able to associate them correctly, and thus
users might not understand how to complete the form.

Using Adobe Acrobat Pro with documents with interactive forms, you
can make sure that the forms are accessible and usable by making sure
that programmatically associated labels that convey the purpose of
the fields are provided.

The heuristics used by assistive technology will sometimes use the
text label if a programmatically associated label cannot be found.
The TU entry (which is the tooltip) of the
field dictionary is the programmatically
associated label (see Example
3 below and Table 220 in PDF
1.7 (ISO 32000-1)). Therefore, add a tooltip to each field to provide
a label that assistive technology can interpret.

Placement rules

The table below lists the placement rules governing where Adobe LiveCycle
positions labels by default. Note that these rules assume left-to-right
text directionality. If your form requires different positioning (e.g.,
to accommodate PDF documents in languages that use right-to-left text
directionality), see Repositioning form labels in Example
2 below. In general, authors should review label positioning to make
sure it meets the requirements of their particular form.

Control Type

LiveCycle Placement Rules

Text input (including date/time and password fields)

Default placement for the label is to the left of the control.
If this is not possible, LiveCycle will attempt to place it
immediately above the control.

Checkbox

Default placement for the label is to the right of the check
box.

Radio button group

Default placement for the label for each individual radio
button is to the right of the button.
Create a visible caption for the radio button group by creating
static text and placing it to the left of or above the group.
(See Labeling radio buttons below.)

Combo box

Default placement for the label is to the left of the drop-down
list. If this is not possible, LiveCycle will attempt to place
it immediately above the control..

List box

Default placement for the label is above the list box.

Button

LiveCycle automatically places the label on the button;
it does not have to be positioned manually. Ensure that the
button's purpose is properly described in the label text.

As noted in the Description, text labels added in an authoring tool
and then converted to PDF might be visually associated with the fields
but are not programmatically associated, and you should provide a tooltip.

In the Forms menu, select Add or Edit Fields...

For the field you want to edit, access the context menu and select
the Properties dialog.

In the General tab of the Properties dialog, type a description
for the form field in the Tooltip field.

Repeat for all form fields.

The following image shows the Properties dialog with a description
in the Tooltip field.

LiveCycle Designer provides several options for associating descriptive
text and labels with form elements.

For sighted or low-vision users, it is important to properly position
the label adjacent to the control. For screen reader users, you should
also ensure that the label is programmatically associated with the
form control and that sufficient information is provided so that screen
reader users can readily complete and submit the form.

Specifying accessible label text using the accessibility palette

Select an object in your form. The palette shows the object's
accessibility properties.

The label that a screen reader uses does not necessarily have to be
the same as the visual caption. In some cases, you may want to provide
more information about a form element's purpose.

To specify what text should be announced by the screen reader for
a particular object, you can use the Accessibility Palette's Screen
Reader Precedence drop down list. Text is announced in the order shown
in the list: custom text, tool tip, caption, and name.

Depending on the complexity and difficulty of your form, you must
decide which option best suits the requirements for your form.

By default, a screen reader searches for an object's text in order
shown in the image. Once descriptive text has been found for a control,
the search stops.

The image below shows an example of a text field with a visual caption
that might be unclear for screen reader users. One of the fields has
a caption of "Date" but screen reader users may want to know
the preferred date format (shown as screen text). So this text is provided
in the tooltip. Because a tooltip has a higher precedence than the
visual caption, the screen reader uses the tooltip.

Labeling radio buttons

When a screen reader user tabs into a radio button, the screen reader
needs to announce two items:

A general description of the purpose of the group of
buttons

A meaningful description for the purpose of each radio
button

To make radio buttons accessible:

In the Hierarchy palette, select the radio button group.

Select the Accessibility palette and in the Custom Screen Reader
Text box, type the speak text for the group. For example, type "Select
a method of payment."

In the Hierarchy palette, select the first radio button in the
group.

In the Object palette, select the Field tab. In the Item area,
select the item and type a meaningful value for the selected radio
button. For example, type "Cash."

Repeat steps 3 and 4 for each radio button in the group.

Repositioning form labels

The placement of a caption, or label, is important because users expect
them to be found at a particular location adjacent to the control.
For screen magnification users this is even more important, as they
might not be able to view both the control and the label at the same
time.

When you create an object, Adobe LiveCycle Designer automatically
positions the label as specified by the control type (see the table
in the Description above). For example, for a text field, the label
is positioned to the left of the control.

If you need to change the position of the label text (for example,
to accommodate right-to-left text directionality):

Select the object by moving the focus to it.

In the Layout palette, under Caption at the bottom of the palette,
select the position of your object from the Position drop-down list.

The resulting repositioned label is shown below. The label for the
Date text field has been moved from the left of the field to the line
above the field.

Example 3: Adding a tooltip to interactive form controls

The following code fragment illustrates the use of the TU entry to
provide a tooltip (or programmatically associated text label) for a
form field. This is typically accomplished by an authoring tool.

Tests

Procedure

For each form control, verify visually that the label is positioned
correctly in relation to the control.

For each form control, verify that the name is programmatically
associated with the control by one of the following:

Open the PDF document with a tool that is capable of showing
the name associated with the control and verify that the name
is associated correctly with the control.

Use a tool that exposes the document through the accessibility
API, and verify that the name is associated correctly with the
control.

Expected Results

#1 and #2 are true.

If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.